Cold chain · Seafood & fresh meat

    A three-degree window — where both directions are fatal.

    Chilled fish and fresh meat hold in a sliver near 0 °C: dip below roughly −1 °C and ice crystals wreck the texture for good; drift above the ceiling and shelf-life burns by the hour while histamine and pathogens build — none of it reversible. The most expensive failure isn't a dramatic spike, it's the quiet drift that averages hide. Navixy evaluates every packet and its rate of change against a tight per-load corridor.

    Get a deployment plan Cold-chain overview
    1-Wire probes · ~1/16 °CCorridor with a floor and a ceilingPer-packet rate-of-changeHACCP-ready time-temperature record
    A whole fish and salmon fillets resting on crushed ice on a stainless-steel chilled counter
    Anatomy of a slow drift
    Chilled corridor · −1 to +2 °C
    Peak temp
    5.4 °C
    Time above +2 °C
    9 h
    Shelf-life spent
    ≈1.5 days

    A load that never alarms can still be the load that fails

    Here the harm is a cumulative function of time × temperature, not a single threshold crossing — three different biologies make the same point. So Navixy evaluates every packet and the delta between packets, not a sampled mean.

    The slow drift spends shelf-life the alarm never sees

    A load that rides at 5 °C instead of 0 °C for a day never trips an absolute limit — it just arrives looking fine with most of its sellable life gone. Per-packet rate-of-change rules catch the climb while it is minutes old; IoT Query reports the shelf-life spent, not a comfortable mean.

    Same load, no alarm — half the shelf-life already spent
    Held on ice 0 °C≈14 days left
    Quiet ride at 5 °C≈7 days — halved
    Warm leg at 10 °C≈3.5 days — halved again
    day 0shelf-life remainingday 14

    Raising fish from 0 → 4.4 °C roughly doubles the spoilage rate and halves remaining shelf-life (Oregon State Seafood) — and it never trips an absolute alarm.

    cook
    freeze
    can

    Histamine (scombrotoxin) is heat-stable: once it forms, nothing downstream removes it. ≥200 ppm = adulterated (FDA).

    Histamine is a permanent write-off

    In tuna, mackerel and mahi-mahi, a warm hold builds scombrotoxin — heat-stable, so cooking, freezing or canning can't remove it, and it's a recall-grade adulteration. The only control is time-and-temperature, starting at harvest.

    1 °C

    Listeria grows below 1 °C — RTE cold-smoked fish can gain +1.7 log at 4 °C before it even smells off.

    Listeria grows in the 'safe' cold

    Cold-smoked salmon is ready-to-eat and not cooked, and Listeria is cold-loving — it grows below 1 °C and invisibly. A small warm drift shortens the time to breach the legal limit on a load that still looks perfect.

    10 °C
    doubles · 36 h
    21 °C
    3 h
    27 °C
    1.6 h

    Vibrio in oysters — the doubling time collapses as the meat warms; control is the cumulative integral, not a threshold.

    Vibrio is a clock, not a threshold

    In raw oysters, Vibrio growth accelerates exponentially as the meat warms — the doubling time collapses from ~36 h at 10 °C to ~1.6 h at 27 °C. Control plans grade lanes by time-to-cooling, so you must report the integral.

    temp&&
    O₂&&
    level

    Live haul: warm water raises O₂ demand while lowering O₂ supply — one compound rule watches temp, dissolved oxygen and tank level together.

    Live haul needs more than a thermostat

    Live fish and shellfish travel in low-volume tanks where oxygen must be actively held. Warm water raises O₂ demand while cutting O₂ supply, so the alert has to be multi-parameter — temperature, dissolved oxygen and level on one rule.

    Anatomy of a slow drift

    No spike, no absolute alarm — and half the shelf-life gone

    The classic seafood failure isn't a dramatic excursion; it's a quiet ride a few degrees too warm. A static limit may never trip, but spoilage is roughly linear with temperature, so the load arrives looking fine with its sellable life spent. A per-packet rate-of-change rule catches the climb while it is minutes old.

    Chilled corridor · −1 to +2 °Clive shipment telemetry
    2 °C-1 °C
    IcedWarm dockLine-haulReceiving
    Condition timeline
    • Loaded on ice at 0 °C — squarely in band
    • A tired door seal and a warm dock start a slow climb
    • Rate-of-change alarm: +0.8 °C/h — still only 2.6 °C
    • Rides at ~5 °C: no spike, but the spoilage rate has doubled
    • Cumulative time-above-2 °C crosses the shelf-life budget
    • Delivered — record shows ≈1.5 days of life already spent
    Proof of condition
    Peak temp
    5.4 °C
    Peak temp
    Time above +2 °C
    9 h
    Time above +2 °C
    Shelf-life spent
    ≈1.5 days
    Shelf-life spent
    How it's built

    From a razor-thin band to an audit-ready record, in four moves

    The same composable platform behind fleet and field operations, configured for the tightest corridor in the cold chain — on hardware you already approve.

    1. 01

      Sense at the two diagnostic spots

      High-resolution 1-Wire probes (~1/16 °C, no field calibration) at the door and the evaporator, streaming every packet, with reefer setpoint and door read over CAN / J1939 alongside the in-load probes.

    2. 02

      Decide on a floor, a ceiling, and a slope

      IoT Logic enforces a corridor with both bounds, evaluates every packet against the previous one for rate-of-change, and runs a compound temp + dissolved-oxygen + level rule for the live-haul edge case.

    3. 03

      Act while the load is still saveable

      The early rate-of-change alert means re-ice, fix the unit, or close the door before a quiet drift becomes spent shelf-life or an irreversible histamine build — not a post-trip discovery at the dock.

    4. 04

      Prove the exact metric the auditor wants

      IoT Query writes the cumulative figure this category needs — MKT, time-above-4.4 °C toward the histamine limit, equivalent-days-on-ice, or an NSSP-style Vibrio integral — exported for a Seafood HACCP / FSMA / NSSP audit and to settle a rejected-load dispute.

    Hardware & integrations

    1-Wire at the two diagnostic spots — every packet, never averaged

    A three-degree corridor is only observable with the right sensor in the right place, read at full resolution. Navixy normalizes high-resolution 1-Wire probes, reefer J1939, door and GPS into one data model across 2,500+ device models — and, for live haul, dissolved-oxygen and level on the same device.

    • High-resolution 1-Wire (~1/16 °C, no field calibration) makes a 3-degree band and a slow drift observable — a ±0.5 °C-class tag can hide the entire window
    • Two diagnostic placements: at the door (warm-air ingress on every open) and at the evaporator (unit fault + cold back-wall freeze risk); add front / mid / rear on a long trailer
    • Per-packet evaluation, never sampled or averaged — the device streams every reading and the platform evaluates each one and its delta to the previous
    • Analog / RS-485 dissolved-oxygen + water-level probes bind to the same device as the temperature probe, so one compound rule serves the live-haul tank
    • Reefer CAN / J1939 and offline store-and-forward (no gaps) — because the time-temperature integral is meaningless with holes in the record; ships white-label over an open API
    1-Wire bus · placement is a design decision
    tracker
    1-Wire
    Door+1.8 °C
    Evaporator−0.4 °C
    Front+0.6 °C
    Rear+0.9 °C
    ~1/16 °C resolutionno field calibrationup to 4 probes / trackerstore-and-forward — no gaps

    The two diagnostic spots earn their place: at the door catches warm-air ingress on every open, at the evaporator catches a unit fault and the cold back-wall freeze risk. For live haul, analog / RS-485 dissolved-oxygen and level probes ride the same device so one compound rule sees temp + O₂ + level; reefer CAN / J1939 is read alongside — never instead of — the in-load probes.

    A whole fish and salmon fillets resting on crushed ice on a stainless-steel chilled counter
    In-load probe−0.3 °C
    ~15%
    of all fish & seafood is lost or wasted along the chain (WEF / FAO)
    Measure the integral, not the snapshot

    Air is not product — and the mean is not the trip

    Spoilage, histamine and pathogen growth are all cumulative functions of time and temperature, realized days later as a texture complaint, a short code-life, or a recall. Reading the product itself at full resolution — and recording the integral — is what turns a tight, unforgiving band into a number you can act on and defend.

    • Independent in-load probes at the door and evaporator, not just the reefer's return-air sensor
    • A cumulative time-temperature record — MKT, time-out-of-range, equivalent-days-on-ice
    • A gap-free, exportable log that supports Seafood HACCP / FSMA / NSSP and defends a claim
    The other irreversible failure: the freeze a vaccine never shows
    FAQ

    What seafood & meat teams ask

    Why isn't a freezer 'safe' for fresh fish and meat?
    Because freezing is itself a defect for chilled product. At about −1 °C lean fish (and ~−1.5 °C meat) begin forming ice crystals that rupture cell structure and ruin texture on thaw. The target is a sliver just above the freezing point — near 0 °C on ice, or a controlled −1 to −3 °C superchill — so the corridor needs a floor as well as a ceiling, which a single 'keep it cold' threshold can't express.
    If the load never set off an alarm, why did shelf-life arrive short?
    Spoilage is roughly linear with temperature. A quiet ride at 5 °C instead of 0 °C roughly doubles the spoilage rate and halves remaining shelf-life — about 1.5 days of life spent per 12 hours at ~7 °C — without ever crossing a hard limit. Average-only monitoring hides it; per-packet rate-of-change rules catch the drift while it is minutes old.
    Can spoiled-fish (histamine) poisoning be cooked or frozen out later?
    No — it's irreversible. Histamine (scombrotoxin) is heat-stable: cooking, freezing, canning or smoking will not destroy it, and once it forms the reaction can't be reversed. That makes it a permanent write-off and a recall trigger, so the control is purely time-and-temperature, starting at harvest (FDA: ice to ≤ 4.4 °C within 12 h of death).
    Refrigerated oysters and smoked salmon are cold — why are they still risky?
    Both defeat the 'cold = safe' intuition. Vibrio in oysters grows exponentially faster as the meat warms — doubling time falls from ~36 h at 10 °C to ~1.6 h at 27 °C — so summer plans demand icing within ~2 h of harvest. Listeria is cold-loving and grows below 1 °C, invisibly gaining over 1.7 log at 4 °C before the product seems off. Both are cumulative, not thresholds.
    Doesn't monitoring the reefer's own temperature cover it?
    No — air temperature is not product temperature. The reefer's sensors sit in the unit, not the load. Put high-resolution 1-Wire probes (~1/16 °C) at the door and the evaporator, evaluate every packet, and read the reefer over CAN / J1939 alongside — not instead of — independent in-load probes.
    What does live seafood transport need beyond temperature?
    Dissolved oxygen and water level, on the same rule. Live fish travel in low-volume tanks where warm water raises oxygen demand while lowering oxygen supply, so a thermostat alone can't protect them. IoT Logic compound conditions watch temperature, dissolved oxygen and level together and fire before fish die — the edge case single-parameter tools can't serve.
    How does Navixy turn this into something auditable?
    By writing the exact cumulative metric in IoT Query. Rather than a fixed min/max report, IoT Query computes MKT, time-out-of-range, time-above-4.4 °C toward the histamine budget, equivalent-days-on-ice, or an NSSP-style Vibrio integral in SQL — exported on a schedule via API or PDF to support a Seafood HACCP / FSMA / NSSP audit and settle a rejected-load dispute.

    Hold the three-degree line — and prove you held it

    Tell us your species, lanes, and packaging. We'll map the high-resolution 1-Wire placements, the floor-and-ceiling corridor and rate-of-change rules, the compound live-haul logic, and the cumulative HACCP / FSMA / NSSP records — so a razor-thin, unforgiving band becomes an alert you can act on and a record you can defend.

    Get a deployment plan See how it's built